1. Field of the Disclosure
This document relates to an optical film and a display device having the same.
2. Description of the Background Art
A liquid crystal display (LCD) is an electronic device that changes various electrical information generated from various elements to visual information by using a change in a liquid crystal transmission and transfers it.
The general LCD comprises a liquid crystal panel that displays an image according to a drive signal and a data signal applied from an external source and a backlight unit disposed on a rear surface of the liquid crystal panel in order to illuminate the liquid crystal panel.
The backlight unit comprises a light source unit, a reflection sheet, and an optical film.
The light source generates light of a certain wavelength.
The reflection sheet reflects light that has not been made incident on the optical film, among light generated from the light source, to allow the light to proceed in the direction of the liquid crystal panel.
The optical film comprises a diffusion sheet, a prism sheet, and a protection sheet.
Light outputted toward the liquid crystal panel after being generated from the light source passes through the diffusion sheet. At this time, the diffusion sheet distributes the incident light, preventing the light from concentrating partially and making luminance uniform.
As the light passes through the diffusion sheet, its luminance is sharply degraded, so in order to prevent the degradation of the luminance, the prism sheet is used.
FIG. 1 is a perspective view of the prism sheet according to the related art.
With reference to FIG. 1, the prism sheet 100 comprises a prism support unit 130 and a plurality of prism configuration parts 110 formed side by side on the entire surface of the prism support unit 130.
The prism configuration parts 110 comprise side parts each with a first side 112 and a second side 114 and substantially having an equilateral triangular shape when viewed from the front side. The angle between the first and second sides 112 and 14 is generally 90°, and may vary according to a selection.
As the plurality of prism configuration parts 110 are continuously formed on the prism support unit 130, there are formed valleys 118 and peaks 116 alternately. Light made incident on the prism support unit 130 of the thusly constructed prism sheet 100, it is refracted while passing through the prism configuration pails 110. Accordingly, the light made incident at the low angle is concentrated toward the front side, enhancing luminance within the range of an effective viewing angle.
However, when the prism configuration parts 110 of the related art prism sheet 100 contact with a smooth surface of a different optical film, a wet-out phenomenon occurs, damaging the optical film.
Moreover, a moiré phenomenon occurs due to interference of periodical patterns between pixels constituting the liquid crystal panel and the prism configuration parts 110 of the prism sheet 100, degrading the screen display capability.